This invention relates to thread roll attachments for screw thread machines and the like, and more particularly to an improved thread rolling head or attachment which carries two thread rolls, and which is substantially easier to set up and adjust than prior such attachments. Even more particularly, this invention is related to an improved such attachment which is particularly suited for use as a tangential thread roll attachment.
A thread rolling attachment somewhat similar to that disclosed herein is disclosed in U.S. Pat. No. 4,617,816, which is owned by the Assignee of this patent application. For example, the above-noted patent discloses an attachment including a pair of arms that are pivotally mounted intermediate their ends on a yoke, so that two thread rolls, which are supported on the arms can be forced radially into rolling engagement with opposite sides of a piece of rotating bar stock in order to form threads on the stock. The arms are actuated by a wedge element which is manipulated by a fluid pressure operated piston. Although such prior art mechanism is suitable for introducing the thread rolls radially into diametrally opposite sides of the rotating bar stock, it has been found to be most desirable to provide a more accurate and easier means of manipulating the wedge element prior to engagement of the thread rollers with the rotating bar stock. Moreover this accuracy is particularly important in mechanisms of the type which utilize tangential engagement of the thread rolls with the bar stock.
Accordingly, it is an object of this invention to provide an improved, rather inexpensive and compact means for manipulating a wedge element of the type that is employed for accurately positioning the threading rolls of a threading roll attachment.
Still another object of this invention is to provide an improved thread rolling head of the type described in which the associated threading roll adjusting mechanism can be easily and readily manipulated manually by an operator to provide very accurate spacing between the threading rolls prior to engagement thereof with the associated workpiece.
A still further object of this invention is to provide an improved thread rolling head which is mounted on means for effecting tangential engagement of the threading rolls with the work that is to be threaded.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.